In a study conducted between June 2016 and October 2021, 296 older adults with mild cognitive impairment, a condition often preceding Alzheimer’s disease, were assigned to undergo either aerobic exercise or stretching for 12 months. The participants who received these treatments showed no cognitive decline, while a matched group undergoing usual care continued to decline. This finding was described as “remarkable and encouraging” by Maria Carrillo, PhD, chief science officer of the Alzheimer’s Association.
Recently, Leqembi and Kisluna, the first disease-modifying drugs to slow the progression of early-stage Alzheimer’s disease, have received significant attention. However, these drugs have onerous treatment regimens, high costs, and questionable benefits, leading many health professionals to question their worth for patients. The study’s results suggest that exercise could be a less costly but equally effective remedy.
Research has already established that regular exercise is one of the top tools for preventing Alzheimer’s disease. A meta-analysis of 16 studies involving 160,000 subjects showed that physically active people are 45% less likely to develop Alzheimer’s. Historically, scientists have been less certain that exercise can meaningfully stall Alzheimer’s once it takes hold.
The Phase III EXERT trial provided one of the strongest recent examples that exercise can stall the disease. The participants’ cognitive decline effectively stalled during the year-long trial, despite the average subject being in their seventies. Another shorter trial featuring fewer participants with actual Alzheimer’s disease had similar findings.
Aerobic exercise, which elevates heart rate, tends to be most effective at boosting cognition. Resistance training, while still beneficial, is less so. Three to four bouts of aerobic exercise per week lasting roughly 45 minutes each seem to produce the best results.
Various mechanisms could explain exercise’s apparent ability to slow Alzheimer’s disease. These include increasing blood flow to the brain, reducing markers of inflammation in the central nervous system, boosting brain size, and greatly boosting the production of BDNF, a compound that regulates various functions that help the brain grow and work smoothly. In Alzheimer’s patients, BDNF is often depleted.
By 2050, it is projected that nearly 100 million people could suffer from Alzheimer’s disease as the world’s elderly population over 65 balloons to nearly 1.5 billion. Considering the social, human, and economic costs of this devastating disease, cost-effective solutions like exercise are indispensable for both treatment and prevention.
